A T-boat (small passenger vessel) operating on a lakes, bays, and sounds route is required by 46 CFR §180.68 to carry a minimum of how many hand red flare distress signals?

Why B is correct

46 CFR §180.68(b)(1) requires three hand red flare distress signals (approval series 160.021) for a vessel on a lakes, bays, and sounds, or rivers route. Six hand flares are required only for oceans, coastwise, limited coastwise, or Great Lakes routes under §180.68(a)(1).